Hydraulic turbine with by-pass valve



3-Sheets-Sheet 1 Filed NOV. 21, 1955 FIG.

FIG.2

INVENTOR FRANK wHlTTLE BY @HPM c CLJ Hls AGENT Dec. 23, 1958 F. WHITTLEHYDRAULIC TURBINE WITH BY-PAss VALVE 3 Sheets-Sheet 2 Filed Nov. 2l,1955 y /7// lnllllllllll. Illllilnnln Y 4 O 7 2 l mw INVENTOR FRANKWHITTLE BY 5.51.16 Culi;

HIS AGENT Dec. 23, 1958 F. wHn-TLE 2,865,602

HYDRAULIC TURBINE WITH BY-PASS VALVE Filed Nov. 21. 1955 5 Sheets-Sheet3 FIG. 4

INVENTOR;

FRANK WHITTLE BY; .HJC-vdtg Hls AGENT HYDRAULIC TURBINE WITH BY-PASSVALVE Frank Whittle, Dunsford, England, assignor to Shell DevelopmentCompany, New. York, N. Y., a corporation of Delaware ApplicationNovember 21, 1955, Serial No. 547,930

Claims priority, application Great Britain December 10, 1954 Claims.(Cl. Z55-4) prising a hydraulic turbine, which is located near the lowerend of a drill string and is arranged to drive a rotary drill bit. Thedrill string is kept stationary or may be rotated only very slowly so asto prevent it sticking in the borehole.

The hydraulic turbine is driven by a drilling fluid or mud flush whichis pumped down through the drill string,

and which, after having passed through the turbine blading, is ejectedtrough jet openings provided inthe rotary drill bit and directed ontothe cutting edges of the rotary drill bit to cool them and to remove thecuttings. The mud ilush then circulates back up the borehole outside thedrill string to the surface.

When operating such a turbine-driven drill bit at the Ebottom of aborehole, attention has to be paid to the speed of the turbine as thebit passes through formations of varying hardness, as on the one hand,if the speed drops below a certain value, the turbine may stop, and onthe other hand if the speed is too high, the bit as well as the turbinebearings are liable to excessive wear. In addition, it has to be bornein mind that excessive deviations from the design speed of a turbineresult in a very low efciency of operation.

It is also obvious that very high speeds are reached if, whilemaintaining the mud flush circulation, the bit is lifted from the bottomof the borehole. The turbine then tendsl to race, with resultant rapiderosion of the turbine blading and excessive wear of the bearings.

Further, in the event of the 'bit becoming stuck, a substantial loss ofcirculation pressure in the turbine is experienced when an attempt ismade to free the bit by washing action, as in this case the whole mudflush circulation has to be pumped through the immovable turbine whichacts as a restriction in the line.

Finally, when it is required to pump vlost circulation material throughthe drill string in order to seal the walls of the borehole, such lostcirculation materiall has to pass through the turbine blading and as itis of a sealing nature, there is the risk that it will block the turbineblading and consequently necessitate withdrawal of the turbine from theborehole to free its fluidpassages.

Accordingly, it is a principal object of the. present invention toprovide a Well drilling assembly comprising a hydraulic turbine, forlocation near the lower end of a drill string, and a rotary drill bit,the turbine being arranged to drive the rotary drill bit and itselfbeing capable of being driven by mud flush or other uid which is pumpeddown through a drill string, in which assembly means isV provided forautomatically directing the flow of mud flush through a channelby-passing the turbine blading, when there is no load on the rotarydrill bit.

l Another 4object of the present invention is to provide a hydraulicturbine capable of being mounted near the lower end of a drill string todrive a rotary drill bit,

lwhich, turbine includes an axially movable member arranged toV be fixedin relation to a rotary drill bit and to inuence the flow of liquidthrough the turbine in, such a way kthat the turbine blading isby-passed when there is no load on the rotary drill bit.

A further object of the presentvinvention is to provide a rotary drillbit adapted to be connected to a hydraulic turbine in such a manner thatit is driven by the turbine rotor, but is capable of axial movement inrelation to it.

In one arrangement, the axially movable member of Ithe turbine may bemade as part of an assembled unit comprising also the rotary drill bit.In such a case, it is an object of the present invention to provide ahydraulic turbine capable of being mounted near the lower end of vadrill string to drive a rotary drill bit, in which turbine means,including a hollow rotor shaft, are provided to direct hydraulic flowthrough the turbine blading, or alternatively to by-pass the blading.

Furthermore, it is an object of the present invention to provide an`assembly comprising primarily a rotary drill bit and an axiallyextending member fixed toit, the said member being adapted to cooperatewith the above-mentioned hollow rotor shaft in such a manner that, when,during operation, the load on the drill bit is reduced or withdrawn, thehydraulic iluid is caused to by-pass the turbine blading.

The bit may be mounted telescopically on the turbine rotor shaft, avalve system being provided, whichis adapted to be operated by axialmovement of the bit relative to the rotor shaft, so that in the positiontaken up by the bit when there is no load on it, the ow of mud flushpasses through a channel by-passing the turbine blading.

In one assembly in accordance with the invention, the turbine rotorshaft is hollow, the interior thereof communicating with the turbineinlet, and isy provided with ports connecting the turbine outlet and theinterior, and a valve seating located inthe interior between the portsandk the point or points of communication with the turbine inlet, andthe rotary drill bit is adapted to be mounted on the rotor shaft and toslide telescopically with respect to it and is provided with a hollowsleeve which slides axially inside the rotor shaft, the sleevev beingprovided with ports n the walls thereof and a valve member on the sideof the ports remotey from the bit, the arrangement being such that whenthe bit is loaded and the sleeve is pushed into its inner positionwithin the interior of the rotor shaft, the ports in the rotor shaft andthe sleeve are in the register and the valve member and valve seatingcooperate to close the interior of the rotor shaft at the valve seating,while, when the load is removed and the` sleeve is pulled out to itsouter positionl relative` to the rotor shaft, the ports in the rotorshaft are` closed by the sleeve and the valve member andv seating areapart leaving open` the passage through thefinterior of the rotor shaft.In order to improve thesealing of the ports in the rotor shaft bv thesleeve when the latter is in its outer position relative to the rotorshaft, the rotor shaft may be provided with an additional valve seatingagainst which a valve member in the form of a. step or projection on theouter surface of the sleeve bears whenV the sleeve is pulled out to thesaid other extremeposition.

When, under certain conditions solid particles may settle out from themud ush present in the turbine when the flow by-passes the turbine, avnumber of small openings may be provided in the. sleeve, which openingscooperate with the ports in the rotor shaft in the outer position of thesleeve. so as to permit a slight circulation of fluid through thepassages of theturbine.

According to a further aspect of the invention the hydraulic turbine istelescopically arrangedv with respect to .the drill str-ing, avalvesystem being providedl which is adapted to be operated by axialmovementnf the `hydraulic airain@ and the bit relative to the drinstring,

such that in the one extreme positionpassageof mud flush from the drillstring to the hydraulic turbine is substantially blocked and directpassage of mud flush from the drill string to the bore hole ispossible,"whereas in the other extreme position passage of mud flushfrom the drill string to the hydraulic turbine is possible and directpassage of mud flush from the drill string to the bore hole issubstantially blocked. Such a device may comprise telescopicallyoperated ports which control the direct communication between the drillstring and the bore hole and a string-actuated valve which controls thecommunication between the drill string and the hydraulic turbine.

Embodiments of the present invention wlll now be described by way ofexample with reference to the accompanying drawing in which,

Fig. 1 is a longitudinal sectional view of the hydraulic turbine and thedrill bit, when the bit is loaded,

Fig. 2 is a longitudinal sectional view of the hydraulic turbine and thedrill bit, shown in Fig. 1, when the bit is not loaded, and,

Fig. 3 shows a part of Fig. 1 in greater detail.

Fig. 4 is a longitudinal section of a sub with a valve system.

A hydraulic turbine 1,v as shown in the Figs. 1 and 2, is connected tothe drill string or drill collar 2, and comprises a stator casing 3 anda rotor shaft 4 which is supported at its upper end by a bearing 5 andnear its lower end by a bearing 6, which bearing is provided withsuitable sealing means (not shown). The turbine blading 7, consisting ofrotor and stator blades, is located in the space left between the casing3 and the shaft 4.

The rotor shaft 4 is hollow and is provided with openings 8 at its upperend interconnecting its interior and the fluid space at the Yturbineinlet. The rotor shaft 4 is also provided with ports 9 located near itslower end through the wall thereof, interconnecting the turbine outlet,i. e., the lower end of the space between the shaft 4 and casing 3, andthe interior of the shaft 4.

The bit 10 (shown only diagrammatically) is connected to an extension ofthe lower end of the rotor shaft 4 by means of a telescopic arrangement11 having spline means 23 incorporated in it to prevent any rotationalmovement between the bit 10 and the rotor shaft 4. The spline means 23are adapted to move upwardly with a telescoping movement a distanceequal to the height of the telescopic arrangement or housing 11 whichforms the lower end of the rotor shaft 4. The hollow bit stem 13 has bitjet openings 14 in it, through which mud ush is ejected onto the cuttingedges of the bit 10, before finally passing back up the borehole 12 tothe surface.

In addition, a sleeve 15 is provided, the lower end of which is rigidlyconnected to the bit stem 13. The sleeve 15 is provided with ports 16through the wall thereof (Fig. 3), and valve members 17 and 18 locatedabove said. ports. The valve member 17 is formed as an enlarged portionat the upper end of the sleeve 15 and, if desired, may be provided witha steel ring seal or the like as additional sealing means. The` valvemember 17 cooperates with a valve seating 19, installed in the shaft 4,and provided with passages 24 and 2S which are closed by valve 17.

As shown in Fig. 3, the sleeve 15 is in its raised position, and theports 16 are in full register with the ports 9 in the shaft 4, while theupper valve member 17 closes 'the passages 24 and 25 through the valveseating 19,

which may comprise a spider-like perforate plate xedly located in theinterior of the hollow shaft 4. The lower valve member 18 of the valvesleeve 15, which is formed as a tapered portion of said sleeve 15, isadapted to cooperate with the valve seating 20 provided in the interiorof the hollow shaft 4 below the ports 9, to assist 'in sealing the ports9 when the sleeve 15 is in its lower position.

Y V A limited number of small openings 21 (only one of blading 7 may berecessed into the stator housing 3 and rotor shaft 4, respectively, withthe rotor shaft being formed, if desired, in two portions threadedtogether.

As shown in Fig. 1, the bit 10 is in contact with the bottom of theborehole 12, and is loaded, so that in consequence the bit stem 13 isbrought up against abutments 11 provided on the lower end of the hollowshaft 4, by the weight of the turbine and by part of the weight of thedrill string and drill collars. In this case the sleeve 15, which isconnected to the bit 10, is pushed in to its upper position (see alsoFig. 3). Now the mud flush, which is pumped down through the drillstring 2, passes through the turbine blading 7 and is ejected from theturbine outlet through the ports 9 and 16 to the interior of the sleeve15, whence it passes through the hollow drill stem 13 and is ejectedthrough the bit jet openings 14 of the drill bit 10.

On ,lifting the drill string 2 off the bottom of a well borehole, theweight on the bit may decrease to zero, and the telescopic arrangement11 operates so that the sleeve 15 is pulled out to its lower position(Fig. l2) by the combined action of the gravity and the pressure dropprevailing across the bit jet openings 14. In this position, the ports 9and 16 are no longer in register while at the same time the valve member17 is drawn away from the valve seating 19. An additional sealing isobtained by the valve member 18, virtually a projection or step on theexternal surface of the sleeve 15, seating on to the valve seating 20.Now, the mud flush flowing through the drill string 2, passes downthrough the openings 8, the passages 24 and 25 through the valve seatingplate 19 and further through the interior of sleeve 1,5 to the hollowbit stem 13, thus by-passing the turbine .blading 7, and is ejected intothe borehole 12 through the bit jet openings 14. Thus, the turbine stopsrotating.

In the position of the sleeve, as shown in Fig. 2, the small openings 21(only one of which is shown in Fig. 3) come into communication with theports 9. This results in a very small tlow of mud flush through theturbine, thus preventing settling out of solid particles from the mudflush remaining in the turbine when it is not in action. The circulationrate through the turbine is now determined by the total area of theopenings 21, which may oe so designed that the said rate is insufficientor only just sufficient to rotate the turbine.

Figure 4 shows a sub with a screw thread 23 for connection with ahydraulic turbine and a screw thread 24 for connection with the drillstring. An inner sleeve 25 with splines 26 is connected to the upperpart 27 of the sub, and an outer sleeve 28 with splines 29 and ports 30is connected to the lower part 31 of the sub. In the lower part of thesub a valve mechanism 32 is provided, with a closing spring 33.

During normal drilling operation the sub is positioned as shown inFigure 4, with valve 32 open, permitting the ow of liquid from the drillstring to the hydraulic turbine. When it is desired not to direct fluidthrough the turbine, the driller raises the drill string, permitting theinner splines 26 to move up relative to the outer splines 29, wherebythe ports 30 4are uncovered and the fluid can escape directly to thebore hole. Leaking of fluid to the turbine is prevented by valve 32,which is closed by the spring 33.

It is also possible to form the apparatus according to Figure 4 or asimilar device as an integral part of the hydraulic turbine (in whichcase screw thread 23 is omitted). M -f As compared with the systemaccording to Figures 1-3,

the device according to Figure 4 has the advantage that the hydraulicturbine can have a solid rotor shaft. The device according to Figures1-3 h-as the advantage that the mud will pass the bit under allcircumstances.

I claim as my invention:

1. A fluid-driven turbine unit adapted to be secured to a pipe stringfor drilling oil and gas wells while a drilling iluid is pumped throughsaid turbine and pipe string, said turbine comprising a stator casing, arotor supported in spaced relationship for rotation within said casing,said rotor being provided with a hollow shaft mounted within said rotorand having the lower end extending downwardly from said casing, turbineblading carried on the inner wall of said casing -and the outer surfaceof said rotor, a drill bit fixedly mounted against radial movement andtelescopically mounted for axial movement on the downwardly-extendingend of said rotor shaft, port means near the upper end of said rotorshaft interconnecting the interior of said shaft and the interior of thepipe string, port means through the wall of said hollow rotor shaftbelow said turbine blading for admitting fluid discharged from saidblading into the lower portion of said shaft above the bit, lrst valvemeans operatively secured to said telescoping bit for opening said portmeans when the bit is on the bottom of the well, and second valve meansoperatively secured to said telescoping bit and within said hollow rotorshaft for directing the flow of drilling fluid through said hollow shaftand around said turbine blading as the drill bit is raised oli thebottom of the well.

2. A uid-driven turbine unit adapted to be secured to a pipe string fordrilling oil `and gas wells while a drilling fluid is pumped throughsaid turbine and pipe string, said turbine comprising a stator casing, arotor supported in spaced relationship for rotation within said casing,said rotor being provided with a hollow shaft mounted within said rotorand having the lower end extending downwardly from said casing, turbineblading carried on the inner wall of said casing Aand the outer surfaceof said rotor, a splined section formed on the downwardly-extending endof said shaft, -a drill bit xedly mounted against radial movement andtelescopically mounted for axial movement on the splineddownwardlyextending end of said rotor shaft, port means near the upperend of said rotor shaft interconnecting the interior of said shaft andthe interior of the pipe string, port means through the wall of saidhollow -rotor shaft below said turbine blading for admitting fluiddischarged from said blading into the lower portion of said shaft abovethe bit, rst valve means operatively secured to said telescoping bit foropening said port means when the bit is on the bottom of the well, andsleeve valve means operatively secured to said telescoping bit andwithin said hollow rotor shaft for directing the ow of drilling uidthrough said hollow shaft and around said turbine blading as the 0 drillbit is raised off the bottom of the well.

3. A turbine unit adapted to be connected between Ia drill string and adrill bit to rotate said bit, said unit comprising a tubular statorattachable to the drill string, a tubular rotor coaxially supported forrotation within said stator, an annular space being formed between theinner wall of the stator and the outer wall of the rotor, stator 'androtor blades attached in said annular space to said two wallsrespectively, telescoping spline means attaching the rotor to the drillbit, a sleeve mounted within the rotor coaxially therewith and attachedto the drill bit for telescoping motion with regard to said sleeve,radial port means through the rotor and the sleeve, a valve seatprovided with axial port means mounted within the rotor, valve meanscarried by the sleeve to close said axial port means at the end of theupward telescoping motion of the sleeve, the radial port means throughthe rotor and the sleeve being axially spaced to register with eachother at the end of the downward stroke of the sleeve.

4. A fluid-driven turbine unit adapted to be secured to a pipe stringfor drilling oil and gas wells while a drilling fluid is pumped throughsaid turbine and pipe string, said turbine comprising a stator casing, arotor supported in spaced relationship for rotation within said casing,said rotor being provided with a shaft mounted within said rotor andhaving the lower end extending downwardly from said casing, turbineblading carried on the inner wall of said casing and the outer surfaceof said rotor, a drill bit iixedly mounted against radial movement andtelescopically mounted for axial movement on the downwardly-extendingend of said rotor shaft, longitudinal conduit means through said rotorshaft bypassing said turbine blading, passage means above and below saidturbine blading for circulating the uid therethrough and through theconduit means in said rotor shaft, and valve means operatively securedto said telescoping bit for directing the flow of drilling fluidthrough. said conduit means and around said turbine blading as the drillbit is raised off the bottom of the well.

5. A fluid-driven turbine unit adapted to be secured to a pipe stringfor drilling oil and gas wells while a drilling iluid is pumped throughsaid pipe string and turbine, said turbine comprising a stator casing, arotor supported in spaced relationship for rotation within said casing,said rotor being provided with a hollow shaft mounted within said rotorand having the lower end extending downwardly from said casing, turbineblading carried on the inner wall of said casing and the outer surfaceof said rotor, passage means above and below said turbine blading forcirculating the iiuid therethrough, a drill bit iixedly mounted on thedownwardly extending end of said rotor shaft for rotation therewith,port means in said hollow shaft interconnecting its interior and thefluid space at the inlet to the turbine blading, thereby bypassing thelatter, and valve means in said hollow shaft and secured to said bit fordirecting the ow of drilling uid through said hollow shaft and the drillbit, and thereby bypassing said turbine blading when the drill bit israised oli the bottom of the well.

References Cited in the tile of this patent UNITED STATES PATENTS1,860,214 Yeaman May 24, 1932 2,591,488 Yost Apr. 1, 1952 2,744,721Hatch May 8, 1956 FOREIGN PATENTS 368,957 Great Britain Mar. 17,-1932l

